1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*
28 * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
29 * All Rights Reserved
30 *
31 * Portions of this source code were derived from Berkeley
32 * 4.3 BSD under license from the regents of the University of
33 * California.
34 */
35
36/* Swap handler for SIGFPE codes.	 */
37
38#include "lint.h"
39#include <mtlib.h>
40#include <errno.h>
41#include <signal.h>
42#include <floatingpoint.h>
43#include <sys/types.h>
44#include <sys/ucontext.h>
45#include <sys/siginfo.h>
46#include <thread.h>
47#include <synch.h>
48#include <stdlib.h>
49
50#ifndef FPE_INTDIV
51#define	FPE_INTDIV	1 /* integer divide by zero */
52#endif
53#ifndef FPE_INTOVF
54#define	FPE_INTOVF	2 /* integer overflow */
55#endif
56#ifndef FPE_FLTDIV
57#define	FPE_FLTDIV	3 /* [floating divide by zero] */
58#endif
59#ifndef FPE_FLTOVF
60#define	FPE_FLTOVF	4 /* [floating overflow] */
61#endif
62#ifndef FPE_FLTUND
63#define	FPE_FLTUND	5 /* [floating underflow] */
64#endif
65#ifndef FPE_FLTRES
66#define	FPE_FLTRES	6 /* [floating inexact result] */
67#endif
68#ifndef FPE_FLTINV
69#define	FPE_FLTINV	7 /* [floating invalid operation] */
70#endif
71
72#if defined(__i386) || defined(__amd64)
73
74#ifndef	FPE_FLTSUB
75#define	FPE_FLTSUB	8 /* subscript out of range */
76#endif
77#ifndef	FPE_FLTDEN
78#define	FPE_FLTDEN	9 /* x86-specific: denormal operand */
79#endif
80
81#define	N_SIGFPE_CODE	10
82
83#else
84
85#define	N_SIGFPE_CODE	8
86
87#endif /* __i386 */
88
89/* Array of SIGFPE codes. */
90
91static const sigfpe_code_type sigfpe_codes[N_SIGFPE_CODE] = {
92	FPE_INTDIV,
93	FPE_INTOVF,
94	FPE_FLTDIV,
95	FPE_FLTOVF,
96	FPE_FLTUND,
97	FPE_FLTRES,
98	FPE_FLTINV,
99#if defined(__i386) || defined(__amd64)
100	FPE_FLTSUB,
101	FPE_FLTDEN,
102#endif
103	0
104};
105
106/* Array of handlers. */
107
108static mutex_t sigfpe_lock = DEFAULTMUTEX;
109
110sigfpe_handler_type ieee_handlers[N_IEEE_EXCEPTION];
111static sigfpe_handler_type sigfpe_handlers[N_SIGFPE_CODE];
112
113static	int	_sigfpe_master_enabled;
114/* Originally zero, set to 1 by _enable_sigfpe_master. */
115
116#ifndef BADSIG
117#define	BADSIG		(void (*)(void))-1
118#endif
119
120static void
121_sigfpe_master(int sig, siginfo_t *siginfo, void *arg)
122{
123	ucontext_t	*ucontext = arg;
124	int		i;
125	int		code;
126	enum fp_exception_type exception;
127
128	lmutex_lock(&sigfpe_lock);
129	code = siginfo->si_code;
130	for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++)
131		continue;
132	/* Find index of handler. */
133	if (i >= N_SIGFPE_CODE)
134		i = N_SIGFPE_CODE - 1;
135	switch ((intptr_t)sigfpe_handlers[i]) {
136	case ((intptr_t)(SIGFPE_DEFAULT)):
137		switch (code) {
138		case FPE_FLTINV:
139			exception = fp_invalid;
140			goto ieee;
141		case FPE_FLTRES:
142			exception = fp_inexact;
143			goto ieee;
144		case FPE_FLTDIV:
145			exception = fp_division;
146			goto ieee;
147		case FPE_FLTUND:
148			exception = fp_underflow;
149			goto ieee;
150		case FPE_FLTOVF:
151			exception = fp_overflow;
152			goto ieee;
153#if defined(__i386) || defined(__amd64)
154		case FPE_FLTDEN:
155			exception = fp_denormalized;
156			goto ieee;
157#endif
158		default:	/* The common default treatment is to abort. */
159			break;
160		}
161		/* FALLTHROUGH */
162	case ((intptr_t)(SIGFPE_ABORT)):
163		abort();
164		break;
165	case ((intptr_t)(SIGFPE_IGNORE)):
166		lmutex_unlock(&sigfpe_lock);
167		return;
168	default:	/* User-defined not SIGFPE_DEFAULT or SIGFPE_ABORT. */
169		(sigfpe_handlers[i])(sig, siginfo, ucontext);
170		lmutex_unlock(&sigfpe_lock);
171		return;
172	}
173ieee:
174	switch ((intptr_t)ieee_handlers[(int)exception]) {
175	case ((intptr_t)(SIGFPE_DEFAULT)): /* Error condition but ignore it. */
176	case ((intptr_t)(SIGFPE_IGNORE)): /* Error condition but ignore it. */
177		lmutex_unlock(&sigfpe_lock);
178		return;
179	case ((intptr_t)(SIGFPE_ABORT)):
180		abort();
181	default:
182		(ieee_handlers[(int)exception])(sig, siginfo, ucontext);
183		lmutex_unlock(&sigfpe_lock);
184		return;
185	}
186}
187
188static int
189_enable_sigfpe_master(void)
190{
191	/* Enable the sigfpe master handler always. */
192	struct sigaction newsigact, oldsigact;
193
194	newsigact.sa_sigaction = _sigfpe_master;
195	(void) sigemptyset(&newsigact.sa_mask);
196	newsigact.sa_flags = SA_SIGINFO;	/* enhanced handler */
197	_sigfpe_master_enabled = 1;
198	return (sigaction(SIGFPE, &newsigact, &oldsigact));
199}
200
201static int
202_test_sigfpe_master(void)
203{
204	/*
205	 * Enable the sigfpe master handler if it's never been enabled
206	 * before.
207	 */
208
209	if (_sigfpe_master_enabled == 0)
210		return (_enable_sigfpe_master());
211	else
212		return (_sigfpe_master_enabled);
213}
214
215sigfpe_handler_type
216sigfpe(sigfpe_code_type code, sigfpe_handler_type hdl)
217{
218	sigfpe_handler_type oldhdl;
219	int		i;
220
221	lmutex_lock(&sigfpe_lock);
222	(void) _test_sigfpe_master();
223	for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++)
224		continue;
225	/* Find index of handler. */
226	if (i >= N_SIGFPE_CODE) {
227		errno = EINVAL;
228		lmutex_unlock(&sigfpe_lock);
229		/* Not 0 or SIGFPE code */
230		return ((sigfpe_handler_type)BADSIG);
231	}
232	oldhdl = sigfpe_handlers[i];
233	sigfpe_handlers[i] = hdl;
234	lmutex_unlock(&sigfpe_lock);
235	return (oldhdl);
236}
237